I have a cousin that lives in Bozeman, Montana, and his observations are pretty much the same. Fall seems to be two weeks later, and spring, two weeks earlier. In area I call home in Eastern Oregon, when I was a child there in the late 40's and early 50's. the winters at 3600 ft regularly had temperatures that hit a low of -40, with the daylight highs of -10 to -20. After Holloween, you seldom had a day with a high above 35. The weather still comes in around Holloween, but the daytime highs are often above 50, and in Burns, one of the coldest places, they now actually get some days of rain in the winter, instead of just snow.
The snow on the mountains goes off much earlier than it used to, and those whose agriculture depends on irrigation from south facing drainages are feeling the affects.